Temperature effects on species specific food uptake of intertidal foraminifera

Author(s)

Julia Wukovits, Annekatrin Enge, Wolfgang Wanek, Margarete Watzka, Petra Heinz

Abstract

Environments populated by intertidal foraminiferal assemblages provide a constant availability of food sources, but are exposed to extreme fluctuations in physical parameters such as seasonal and diurnal changes in temperature. Quality and quantity of available diet and adaptation to physical disturbances can act as factors limiting the abundance of single species.

Here, laboratory feeding experiments were performed on two dominant benthic foraminifera species of the German Wadden Sea/Friedrichskoog (Ammonia tepida, Haynesina germanica) to test the effect of temperature on phytodetritus ingestion. The specimen were fed with 13C &15N labeled freeze dried Dunaliella tertiolecta (green algae) at the start of the experiment and incubated at 20°C, 25°C and 30°C respectively. Samples were taken over a period of two weeks. Foraminiferal cytoplasm was analyzed to investigate differences in carbon and nitrogen uptake derived from the food source.

Both species showed a positive response to the provided food source, while carbon uptake rates of A. tepida were 10-fold higher compared to those of H. germanica. Moreover, increased temperatures caused a significant decrease in the carbon uptake of H. germanica. For A. tepida, slightly increased uptake was observed at 25°C. A general enrichment of nitrogen in the cytoplasm of both species at all temperatures was observed in the progress of the time series.

The results suggest, that higher temperatures act as a stress factor and have a negative effect on the food uptake of H. germanica. For A. tepida, higher carbon uptake rates and the enhanced tolerance of higher temperatures could indicate a competitive advantage in warmer seasons, if the main food source consists of chlorophyte phytodetritus.

Organisation(s)

Department of Palaeontology

Publication date

06-2015

Austrian Fields of Science 2012

106021 Marine biology

Sustainable Development Goals

SDG 14 - Life Below Water

Portal url

https://ucrisportal.univie.ac.at/en/publications/temperature-effects-on-species-specific-food-uptake-of-intertidal-foraminifera(12508ff1-4b3b-40b8-99c4-f553688f4513).html